The invention discloses a squint SAR point target interpolation and section interception method based on a frequency spectrum, and belongs to the field of an SAR. Firstly, an intercepted image containing an SAR point target is transformed into a frequency domain for cyclic extension of a frequency domain image; secondly, a full point target frequency spectrum is obtained through an image segmentation technology, corner point detection is carried out on the intercepted frequency spectrum, and a sidelobe direction is obtained through calculation; thirdly, frequency domain zero padding is conducted on the frequency spectrum, and a point target interpolation image is obtained through inverse Fourier transformation; finally, section maps of the point target in two directions are obtained according to the sidelobe direction obtained through calculation and used for point target performance index calculation.